Exclusive: Secret documents reveal Sydney's newest motorway

Explosive NSW Government documents obtained by 9NEWS show hundreds of homes, sporting fields and parks could potentially be swallowed up by a motorway through southern Sydney.

The proposed route for a road link to Southern Sydney involves a brand new bridge, tunnel through the St George district and up to 15 kilometers of above ground motorway through the Sutherland Shire.

The document is dated August 31, 2017 and marked "Sensitive: NSW Cabinet".

It shows in detail the proposed route for the motorway.

Section B of the motorway would run below Sans Souci. (9NEWS)Section B involves a new bridge over the Georges River. (9NEWS)

Section A is a tunnel which would run from the M5 at Kyeemagh near Sydney Airport to President Avenue at Brighton le Sands.

Section B of the road is also a tunnel from President Avenue to the Captain Cook Bridge. The plans show the motorway would use the existing bridge with a "Captain Cook Bridge duplication" for local traffic.

Section C of the road through the Sutherland Shire is predominantly above ground. The F6 corridor through Taren Point and Sylvania Waters is being used which means homes and local sporting facilities would be acquired by the government.

The controversial Section C of the motorway would wipe out homes in Miranda, Gymea and Kirrawee. (9NEWS)The new motorway is already courting controversy. (9NEWS)